The proposed research focuses on the pharmacokinetics of salicylate in neonates, infants, and children, on the placental and breast milk transfer of salicylate, on mechanisms of transient hepatotoxicity produced by salicylate in children with inflammatory disease, and on the prevention and treatment of salicylate intoxication. Another aspect of the proposed research is concerned with the interaction between salicylate and bilirubin and its clinical implications in neonatal unconjugated hyperbilirubinemia. BIBLIOGRAPHIC REFERENCES: J. B. Houston and G. Levy, Effect of Route of Administration on Competitive Drug Biotransformation Interaction: Salicylamide-Ascorbic Acid Interaction in Rats, J. Pharmacol. Exp. Ther., 198:284 (1976). G. Levy, Clinical Implications of Interindividual Differences in Plasma Protein Binding of Drugs and Endogenous Substances, Chapter 9 in "The Effect of Disease States on Drug Pharmacokinetics", L. Z. Benet, editor, A. Ph. A. Acad. Pharm. Sci., Washington, D. C., 1976, pp. 137-154.